waterproofing servos

[Occupant]

Have watched Bob's videos on waterproofing servos along with several others all informative with most having common threads. From Bobs approach like filling with olive oil (hard for water to intrude if theres already fluid int he cavity. i pulled a couple screws diagonally and flushed with a syringe several times filling the internals then tightened all the screws down. i noted it slowly leaks from the wiring strain relief - added RTV local to seal there. sealing the seam on the body didn't really want to glue with CA or JB weld in case i ever want to open it up. putting an o-ring with grease between the servo horn and body - great idea, done. to seal off the body and potentially the wiring if the RTV doesn't seal everything. changed the servo mount into a cup and potted the servos in RTV molding compound. The cup has two areas to fill, the body side and the connector strain relief area. I used a gap filling CA to draw around the cup to the servo as a temp seal so all the potting material doesn't flow out the bottom after pouring the body side. once cured flip it over and do the connector side. wost case a servo goes bad you can dig out the silicone and repot with a replacement servo.







best i can do blowing up with 2mb pic limit

[Albacore 569]

Could you enlarge the top image please?

[RCSubGuy]

I'll be pulling the servos from the test facility later on today or maybe tomorrow afternoon when Ed gets here. It would be good to not have to fill them with oil, which is a pain. Also, the bigger servos seem to not like the oil, working perfectly, but slowly.

Potting is viable if a reliable seal on the output shaft can be achieved. I'll continue to play with this as it's something our hobby would definitely benefit from.

[He Who Shall Not Be Named]

I'll be pulling the servos from the test facility later on today or maybe tomorrow afternoon when Ed gets here. It would be good to not have to fill them with oil, which is a pain. Also, the bigger servos seem to not like the oil, working perfectly, but slowly.

Potting is viable if a reliable seal on the output shaft can be achieved. I'll continue to play with this as it's something our hobby would definitely benefit from.

You got to hydrostatically balance the goo on the inside with the water on the outside. Otherwise, over time, water will infiltrate within and gobble up the feed-back potentiometer resistive element. Some form of very flexible diaphragm on the servo case will do the trick.

[Occupant]

Update on potting servos. had to fix something else eded up making me change the servo mounts so i got to go thru pulling them and seeing how that goes. was able to use a pic and pull out in just a few pieces. I was impressed at how well this silicone did came off intact in areas with screw threads 4-40 screws and getting into all the little nooks and crannies. I had a bad case of can't wait and used gap filling CA to seal the bottom of the servo to the mount to turn the mount into a top and bottom cup to fill. this time around i made a mold an cast some thin .030" thick silicone gaskets to go between the servo and the mount. Something noteworthy discovered pulling the silicone out ws that near the strain relief some of the oil must have come out (drop or two?) and the silicone adjacent to it was more of a jelly than cured silicone. if this works should be able to do without the olive oil perhaps. FYI use an o-ring with super lube between the housing at the output shaft and an aluminum servo horn to try and seal off the output shaft.

[Occupant]

In case anyones interested here's what the other side of the servo looks like in the mount potted in.